Articular repair following injury or degeneration represents a major clinical problem, with treatment modalities being limited and joint replacement being regarded as appropriate only for the older patient. Limitations in the development of novel technologies for the treatment of articular cartilage defects involve provision of a mechanically functional implant, its fixation within the defect site, and adherence to surrounding host articular cartilage and subchondral bone. The device proposed in this project is intended to overcome these major technical hurdles. The objective is to develop a chondral repair device for articular cartilage, using a hydrogel-fiber composite, formed in vivo, and adhered to the surrounding host articular cartilage. We have recently made two significant technological advances, which together provide an opportunity to develop a new, potentially minimally invasive, approach to articular repair. We have developed an acellular hydrogel-fiber composite material with mechanical properties including compressive modulus, permeability and tensile modulus that are in the range of normal adult human articular cartilage. In addition, we have a technology which causes covalent bonds to be formed between hydrogel polymer and collagen and other proteins of cartilage, providing a mechanism for stable interaction between the hydrogel-fiber implant and the surrounding host articular cartilage. The hypothesis is that an acellular composite construct (a) with mechanical properties similar to native articular cartilage can be formed, (b) adhered to native articular cartilage, and (c) provide a functional articular repair at the time of implantation. The Phase I project has successfully demonstrated the potential for this technology to lead to effective repair in vivo. The objective of the Phase II project is to demonstrate effectiveness and safety of the technology. Specific Aim 1. Complete development of the construct-adhesion technology to reduce the time required to provide the adhesive properties and polymerization of the hydrogel-scaffold construct. Specific Aim 2. Determine the effectiveness of the technology in vivo. Specific Aim 3. Determine the biocompatibility of the technology per ISO 10933. Expected Outcome. When used in vivo, the technology is expected to successfully repair articular defects in the knee, and to show good biocompatibility. If the studies are successful, the results will be used to support a submission to the FDA for initiation of a clinical trial leading to market device approval (PMA). The successful outcome of this project will be the development of a hydrogel-fiber composite construct with the demonstrated safety and effectiveness to repair articular cartilage defects. The results obtained will provide the data necessary for a regulatory submission to the FDA to market the product. [unreadable] [unreadable] [unreadable] [unreadable]